US 3841220 A
Apparatus for safing a munition during normal handling and arming the munition under conditions of sustained free movement through a fluid and a system using such apparatus is provided wherein the apparatus comprises a support structure having a central axis which coincides substantially with a reference axis of the munition and a plurality of fluid devices carried by the structure in a symmetrical manner about the central axis. The apparatus has a common inlet from which the fluid is conveyed to the devices in a simultaneous manner and each device has outlets at least one of which connects with an outlet which is common to all devices. The apparatus employs the energy of the fluid to provide a useable output from the common outlet which is used to arm the munition only under conditions wherein the apparatus is subjected to sustained free movement through the fluid.
Claims available in
Description (OCR text may contain errors)
nited States Patent [191 Murphy SAFING AND ARMING APPARATUS FOR A MUNITION John V. Murphy, Richmond, Ind.
 Assignee: Avco Corporation, Richmond, Ind.
 Filed: July 13, 1972  Appl. No.: 271,529
 US. Cl. l02/70.2 R, 102/81  Int. Cl F42c 151  Field of Search 137/102, 104, 103; 102/81,
[4 1 Oct. 15,1974
Primary Examiner-Samuel W. Engle Attorney, Agent. or FirmJoseph V. Tassone  ABSTRACT Apparatus for saflng a munition during normal handling and arming the munition under conditions of sustained free movement through a fluid and a system using such apparatus is provided wherein the apparatus comprises a support structure having a central axis which coincides substantially with a reference axis of the munition and a plurality of fluid devices carried by the structure in a symmetrical manner about the central axis. The apparatus has a common inlet from which the fluid is conveyed to the devices in a simultaneous manner and each device has outlets at least one of which connects with an outlet which is common to all devices. The apparatus employs the energy of the fluid to provide a useable output from the common outlet which is used to arm the munition only under conditions wherein the apparatus is subjected to sustained free movement through the fluid.
8 Claims, 15 Drawing Figures PATENTED B37 1 51974 3.81 9220 SHEET 10F &
2O PRESSURE 5O REG. -Z.
PATENTEUnm 1 51914 SHEET 3 BF Q FIG? 1 SAFING AND ARMING APPARATUS FOR A MUNITION BACKGROUND OF THE INVENTION SUMMARY This invention provides an improved safing and arming apparatus for a munition, and a system using same, wherein such apparatus is of simple and economical construction and provides reliable operation. The apparatus comprises a support structure which carries a plurality of devices in a symmetrical manner about a central axis. The apparatus has a common inlet from I which fluid is conveyed to the devices in a simultaneous manner and each device has a plurality of outlets at least one of which connects with an outlet which is common to all devices. The apparatus employs the energy of the fluid to provide a useable output from the common outlet and such output is used to arm the munition only under conditions wherein the apparatus is subjected to sustained free movement through the fluid.
Other details, uses, and advantages of this invention will be readily apparent from the exemplary embodiments thereof presented in the following specification, claims, and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show present preferred embodiments of this invention, in which FIG. 1 is a view with parts in cross-section, parts in elevation, and parts broken away illustrating a portion of an exemplary munition which employs the control system of this invention which utilizes one exemplary embodiment of the control apparatus of this invention;
FIG. 2 is a diagrammatic presentation of the control system of FIG. 1 with certain parts shown schematically, others in fragmentary cross-section, and still others in elevation;
FIG. 3 is a perspective view of the control apparatus illustrated in FIGS. 1 and 2;
FIG. 4 is a front view of the apparatus of FIG. 3 with a front portion broken away;
FIG. 5 is a cross-sectional view taken essentially on the line 5-5 of FIG. 3;
FIG. 6 is a cross-sectional view taken essentially on the line 6-6 of FIG. 5;
FIG. 7 illustrates an upper one of the three substantially identical control devices comprising the control apparatus of FIG. 5 with a spherical member thereof under the influence of gravity causing fluid entering therein to be vented through an associated vent port;
FIG. 8 is a view similar to FIG. 7 illustrating the manner in which the vent port is closed during sustained free movement of the control apparatus through the fluid and illustrating the manner in which fluid flows around a spherical member comprising such a device;
FIG. 9 is a top view of the presentation of FIG. 8 with the top end wall removed to further illustrate the flow of fluid around the spherical member;
FIG. 10 illustrates a modification of the device of FIG. 7 which utilizes a hysteresis-inhibiting circuit;
FIG. 11 is a view similar to FIG. 8 illustrating the operation of the hysteresis-inhibiting circuit;
FIG. 12 is a view similar to FIG. 2 illustrating another example of the control system of this invention which employs another embodiment of the control apparatus of this invention and such apparatus utilizes a fluidic NOR component;
FIG. 13 is a view similar to FIG. 3 illustrating a portion of the control apparatus of FIG. 12 minus its associated fluidic NOR component;
FIG. 14 is a cross-sectional view taken essentially on the line 14-14 of FIG. 13; and
FIG. 15 is a view taken essentially on the line 15-15 of FIG. 14.
DESCRIPTION OF ILLUSTRATED EMBODIMENTS Reference is now made to FIGS. 1 and 2 of the drawings which illustrate one exemplary embodiment of the control system of this invention which is designated generally by the reference numeral 19 and such system includes an apparatus 20 and associated cooperating components installed in an associated munition 21. The munition 21 may be of any suitable type which is capable of being launched through a fluid medium or fluid, such as water or air, and in this presentation will be disclosed as a bomb, missile, or the like which is launched from an aircraft. The apparatus 20 has a central axis 22 and is preferably installed in the munition 21 so that its axis coincides substantially with a longitudinal or reference axis of the munition which is also designated by the reference numeral 22.
The apparatus 20 is particularly adapted for safing the munition, i.e., assuring the munition is safe and will not explode during normal handling and such normal handling encompasses storage, installation on an associated aircraft or launch vehicle, and transportation on such vehicle to the release point of the munition. F urther, the apparatus 20 employs the energy of the ambient air to provide a useable output which is used to arm the munition and the arming action occurs only under conditions of sustained free movement of such apparatus through the air. In providing its safing and arming functions the apparatus 20 has inlet means such as an inlet connection 23 for receiving fluid or air under controlled conditions and outlet means such as an outlet connection 24 through which the useable output is provided and as will be apparent from the following description.
The system 19 comprises air intake means in the form of an intake passage 25 provided in the structure 29 of the munition 21 and an air conduit system which is designated generally by the reference numeral 26 for conveying air from the intake passage to the inlet port 23 of the apparatus 20. The system 19 also comprises an air filter 27 of suitable construction suitably installed in the conduit system 26 for filtering any impurities in the air and an air pressure regulator 30 which is installed in the conduit system 26 downstream of the filter 27.
The system 19 also has an air-operated actuator 32 operatively connected to the outlet port 24 by a conduit 33. The detailed operation of the actuator 32 will be described subsequently; however, basically such actuator operates under conditions of sustained free movement or fall through the air to actuate an electrical control switch 35 comprising the system 19. The switch is provided with electrical power from a suitable source on the munition and in a conventional manner and such switch provides an electrical output therefrom through a connection 36 which arms the warhead of the munition 21 in a known manner. For simplicity of presentation, the above-mentioned power source and warhead are not shown in the drawings.
The system 19 has an air bypass passage 37 which is also provided in the structure 29 of the munition. An air flow control valve 38 is provided and has a main body arranged within the bypass passage 37 and such valve is held in what will be referred to as a closed position by a shaft 39 adjoining its outer end. The valve has a coiled compression spring S which tends to urge it outwardly against shaft 39 and for a purpose to be subsequently described.
The intake passage 25 and the bypass passage 37 have sealing plugs 40 and 41 respectively which are installed in position in the exposed outer openings thereof during storage and ground handling of the munition 21; however, once the munition is installed on an aircraft for delivery to a target the plugs 40 and 41 are removed. During normal captive flight of the munition, ram air enters the passage 25 and the construction of the valve 38 is such that there is a continuous bypass of air through inlet 25 and bypass passage 37 which prevents water from collecting and freezing in the inlet passage 25. Although a small amount of air may enter the conduit system 26, it will not operate the apparatus to arm the munition because it does not have sufficient energy.
The munition 21 is released from the aircraft in the usual manner and as the munition is released a lanyard moves the shaft 39 in the direction of the arrow 42, see FIG. 2, from within the bypass passage 37 whereby the valve is ejected from passage 37 by its spring S and passage is now unobstructed. As the munition 21 falls freely through the air toward its target, ram air A enters and builds up in pressure in the conduit system and such air is first filtered by filter 27 and the pressure thereof regulated within predetermined limits by pressure regulator before introduction of such pressure regulated air into the apparatus 20.
As seen particularly in FIGS. 3-6, the apparatus 20 comprises a support structure which in this example is in the form of housing means which is designated generally by the reference numeral 44 and such structure 44 includes a cup-like member 45, a central member 46 and an end member or plate 47. In this example, the outlet means or port 24 for the apparatus 20 is provided in the bottom wall portion of the cup-like member 45 while the inlet means or port 23 for such apparatus is provided in the member 47 and the members 4547 are suitably fixed together in a substantially fluid-tight manner.
A plurality of three devices each designated generally by the reference numeral 50 comprise the apparatus 20 and are carried by the structure 44 in a symmetrical manner about the central axis 22. In this example, portions of devices are provided as an integral part of structure 44.
The devices 50 are in flow communication with the inlet port 23 and the outlet port 24 and operate to assure provision of a useable output from port 24 only when the apparatus 20 and hence all three of the devices 50 are subjected to sustained free movement through the air as produced when the munition 21 is dropped from its carrier aircraft.
Each device 50 has inlet conduit means or a continuous passage in structure 44 which is designated generally by the reference numeral 51 placing the device in flow communication with the inlet port 23. Each device 50 also has first outlet conduit means in the form of a vent 52 and second outlet conduit means in the form of a continuous passage 53 in the structure 44.
The three devices 50 of apparatus 20 are spaced 120 apart in a symmetrical manner about the central axis 22 and equal distances therefrom. Each device 50 comprises an enclosing wall 56 defining a chamber 57 and a spherical member or ball 60 is carried within the chamber. Each enclosing wall 56 of each device 50 is defined by a substantially right circular cylindrical wall 61 adjoined at its opposite ends by opposed end walls 62 and 63.
The inlet and outlet conduit means comprising each device 50 will be provided therein so that they communicate with the chamber 57 and are arranged in the associated enclosing wall in a manner determined by the configuration of such wall. In this example of the invention, each device 50 is often popularly referred to as a unidirectional accelerometer and a passage or opening 64 is provided in its right circular cylindrical wall 61 adjacent the end wall 63. The opening 64 defines the discharge end of inlet conduit means 51 and an inlet opening into the chamber 57.
Each device 50 has a single passage or opening in its end wall 63 which defines the inlet end of the first outlet conduit means or vent 52 and opening 65 defines a first outlet opening 65 from the chamber 57. Another passage or opening 66 is provided in the right circular cylindrical wall 61 at a location generally diametrically opposite from the inlet opening 64 and opening 66 defines a second outlet opening from chamber 57 as well as the inlet end of the second outlet conduit means 53, see FIGS. 7 and 9 of the drawings.
During ground storage and handling of the munition 21 there is no air flow through system 19 and apparatus 20 and hence no danger of arming. During captive flight of the munition 21 the apparatus 20 is oriented and supported essentially as illustrated in FIG. 5 whereupon gravity acts on the spherical members 60 of the two upper devices 50 causing them to rest on the end wall 62. The effective flow areas of the outlet conduit means 52 and 53 and their associated respective openings 65 and 66 are such that during captive flight air flow, even though of limited amount, is through opening 65 and vent 52 as illustrated at 67 in FIG. 7.
However, once the munition 21 is released and there is sustained free movement or flight of such munition and its control device 20, ram air A enters inlet passage 25, is filtered in filter 27, and then enters pressure regulator 30 where it is regulated in pressure and pressure regulated air enters inlet port 23. Each device 50 operates during sustained free movement so that its member 60 covers or blocks its associated vent passage 52 as shown at 70 and 71 respectively in FIGS. 8 and 9 whereupon air flow passes through chamber 57 into opening 66 and outlet conduit means 53. The combined flow of air from all three outlet conduit means 53 of devices 50 is introduced into outlet port 24 to actuate the actuator 32. In particular, the air under pressure acts against a bellows-type diaphragm 73 causing a plunger 74 fixed thereto to be moved in a guided manner through an opening 75 in the housing portion of actuator 32 and against a contact member 76 of the electrical control switch 35. The switch 35 is operatively connected to a suitable electrical circuit, as previously mentioned, to arm the warhead of the munition 21, see FIG. 1.
Flow control means in the form of restrictors 77, see FIG. 2, may be provided to control the flow of air to each device 50. Each restrictor 77 is shown as a fixed restrictor in the drawings; however, it will be appreciated that each restrictor 77 may be adjustable in flow area, if desired.
While the munition 21 is in free flight the flow of high pressure air from the three devices 50 is combined in outlet port 24 to actuate the actuator 32 in the manner previously mentioned. However, if before the actuator 32 is actuated flow through any one of the devices 50 is interrupted the actuator 32 will return to its original position and not operate. Such flow interruption could be produced if the munition 21 is tumbling or experiencing similar adverse free fall conditions. Likewise, with the munition in captive flight prior to release the air flow from each device 50 to outlet port 24 would be insufficient to assure actuation of actuator 32 and hence arming of the munition 21.
Under various conditions of sustained free flight and depending upon ambient conditions, the forces acting upon each spherical member may vary substantially and this is a direct function of the air supply pressure, i.e., the greater the pressure the greater the difference between lock-in and release forces of the apparatus 20 wherein the lock-in force is the force needed to move member 60 in blocking relation to vent 52 and release force is the force needed to move member 60 out of blocking relation to vent 52. To minimize this problem and reduce the hysterisis of each device 50 comprising the apparatus 20, a hysteresis-inhibiting circuit 80 may be provided, if desired, in each device 50 and such circuit is illustrated in FIGS. 10 and 11 wherein FIG. 10 represents a condition similar to FIG. 7 and FIG. 11 represents a condition similar to FIG. 8. Basically the hysteresisinhibiting circuit operates so that regardless of the energy of the ram air entering the inlet passage 25 of system 19 the force acting on each spherical member 60 under all operating conditions likely to be encountered will be controlled within a very narrow range.
The hysteresis-inhibiting circuit 80 for each device 50 is provided in flow communication with its chamber 57 to provide a back-biasing force against its member 60 and help control the movement of such member in a more precise manner. The circuit 80 comprises a connecting passage 81 which is connected between the second outlet conduit means or passage 53 and the first outlet conduit means or vent passage 52. The configuration of passage 81 is in accordance with accepted design of fluidic passages and in a manner known in the art. The circuit 80 also has a fluidic diode 82 which adjoins the vent passage 52.
During captive flight of the munition 21 air flow is through passage 51, the top portion of chamber 57, and out of vent passage 52 in a similar manner as illustrated in FIG. 7. However, once the munition 21 is released from its aircraft and is subjected to free unrestrained movement through the air each of the spherical members covers its associated opening in a manner illustrated in FIG. 11. However, the circuit with its passage 81 and fluidic diode 82 allows partial bleeding of air from passage 53 and the construction of the fluidic diode 82 is such that a pressure is exerted against the spherical member through the vent passage 52 and opening 65 as illustrated at 83. The circuit 80 is constructed so that under all pressure conditions likely to be encountered by a particular munition 21, system 19, and hence apparatus 20 a certain amount of air is metered through the one-way valve or fluidic diode 82 to exert a substantially controlled pressure against its associated member 60 and thereby controll the magnitude of the force with which it is held against the vent passage 52 to block such passage. Therefore, the hysteresis-inhibiting circuit 80 reduces the angular spread between the so-called lock-in and release forces for the apparatus 20 and thereby increases its sensitivity and the operational reliability of the entire system 19.
Another exemplary embodiment of the system of this invention is illustrated schematically in FIG. 12 of the drawings. The system illustrated in FIG. 12 is very similar to the system 19; therefore, such system will be designated generally by the reference numeral 19A and component parts of such system which are similar to corresponding parts of the system 19A will be designated in the drawings by the same reference numerals as in the apparatus 20 (whether or not such components are mentioned in the specification) followed by the letter designation A and not described again in detail.
The pressure regulator 30A of system 19A provides a pressure regulating function which will be apparent from a viewing of FIG. 12 and thus its construction will not be discussed in detail. Further, although the apparatus 20A has numerous component parts which are similar to corresponding parts of the apparatus 20, and these parts will be given the same reference numerals as previously, followed by the letter A, it also employs an NOR fluidic logic device or component 84A and the apparatus 20A will now be described in more detail.
The apparatus 20A comprises a support or housing structure 44A which includes a central member 85A, a cylindrical member 86A supported concentrically around the central member 85A, and an end plate or member 87A, see FIGS. 13-15. The apparatus 20A also comprises three devices 50A spaced apart about a reference axis 22A and the devices 50A are constructed and arranged in a similar manner as devices 50 of apparatus 20.
Each device 50A has inlet conduit means or passage 51A placing its chamber 57A in flow communication with inlet means or inlet part 23A for the apparatus 20A. Each device 50A also has first outlet conduit means or vent means 52A in flow communication with the pressure regulator 30A. In addition, each device 50A has second outlet conduit means 53A in flow communication with the NOR fluidic device 84A of apparatus 20A.
The NOR fluidic logic device 84A has an inlet 90A which is connected to inlet port 23A by a conduit 91A and what is commonly referred to as the power stream for logic device 84A is provided through inlet 90A. The device 84A also has a main outlet 24A which is the main outlet port of apparatus A and the device 84A has another outlet 92A which is connected to regulator 30A by a conduit 93A.
Each device 50A is in the form of a unidirectional accelerometer and also has an enclosing wall 56A defined by a right circular cylindrical wall 61A and opposed end walls 62A and 63A. The inlet conduit means 51A to each device 50A and hence its chamber 57A includes an inlet passage or opening 64A extending through the cylindrical side wall 61A adjacent the end 63A.
The first outlet conduit means or vent means 52A of each device comprises at least one outlet passage and in this example a plurality of two outlet passages or openings 95A and 96A adjacent the end wall 63A, both of which communicate with the chamber 57A and remainder of the vent means 52A. The second outlet means 53A of each device 50A includes a passage or opening 66A in the cylindrical wall 61A and opening 66A is arranged at a location generally diametrically opposite the inlet opening 64A.
[n the apparatus 20A each spherical member or ball 60A comprising each device 50A operates to prevent flow of fluid, air in this example, into its second outlet conduit means 53A while allowing flow into its first outlet conduit or vent means 52A under the conditions of sustained free movement through the atmosphere. This assures that there will be no diversion of the power strea'm entering the NOR logic device 84A through its inlet 90A whereby the full energy of the air stream exits outlet port 24A to provide a useable output. In particular, the energy of the ram air entering intake passage A of system 19A is utilized under conditions of sustained free fall of the munition 21A to actuate the actuator 32A and the electrical switch 35A in the manner previously described.
Under conditions where the munition 21A, system 19A, and apparatus 20A are not under sustained free flight, air flow is provided through an associated outlet conduit means 53A associated with at least one device into the NOR logic device 84A as illustrated at 97A in FIG. 12. Flow into device 84A from one or more conduit means 53A causes the primary power stream of air to be diverted through the outlet opening 92A of the NOR logic device 84A and then through line 93A to the pressure regulator A. With this diversion of the power stream there would be an absence of air flow into the actuator 32A and hence such actuator could not be actuated.
Each system 19 or 19A may be packaged in the nose cone of the fuse comprising an associated munition 21 with the cooperating components of the system supported and arranged in any suitable manner and a typical installation is illustrated in FIG. 1 of the drawings. It is preferred that the apparatus 20 or 20A comprising a particular system be located so that its reference axis 22 or 22A is concentric with the reference axis of its munition and fuse to minimize the effects of the munitions roll, pitch, and yaw.
During normal operation of a typical apparatus 20, for example, filtered air enters the associated pressure regulator 30 which reduces the pressure to approximately 0.33 pounds per square inch gage (psig). This pressure generally represents the ram air pressure of a munition slip stream velocity of 200 feet per second (fps) at standard sea level conditions and the apparatus 20 is designed for optimum performance at 0.33 psig pressure. The pressure regulator 30 assures that optimum performance is obtained at all velocities above 200 fps and when the indicated air speed drops below 200 fps the operating pressure will drop below 0.33 psig and the actuator 35 will not function whereby the munition cannot be armed.
The actuators 32 and 32A associated with apparatus 20 and 20A respectively are provided with means which assure there has been free unrestrained movement or flight a fixed time interval before such actuators will operate. Such means may be referred to as time delay means and in this example comprise orifice means and 100A for apparatus 20 and 20A respectively and such orifice means are provided immediately adjacent their associated air actuators 32 and 32A.
While present exemplary embodiments of this invention, and methods of practicing the same, have been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced within the scope of the following claims.
What is claimed is:
1. In combination: a munition having a reference axis and a control system for said munition; said control system comprising air intake means for receiving ambient air as ram air, an air conduit system for conveying said air from said air intake means, a control apparatus for safing said munition during normal handling and arming said munition under conditions of sustained free movement through said air, said apparatus comprising a fluidic zero G sensor having inlet means for receiving flow of said air from said air conduit system and outlet means for said fluid, an air pressure regulator operatively connected in said air conduit system for regulating the pressure level of said ram air and maintaining its output pressure at a substantially constant level thereby rendering the performance of said zero G sensor independent of said ram air inlet pressure, said apparatus employing the energy of said air to provide a usable output from said outlet means only under conditions of sustained free movement through said air and an air-operated actuator operatively connected to said outlet means, said actuator being actuated by the energy of the air flowing through said outlet means to thereby energize a circuit which arms said munition.
2. A combination as set forth in claim 1 in which the munition is transportable on a carrier aircraft and wherein said control system further comprises a circulating passage in flow communication with said air intake means, removable valve devices for blocking said air intake and an air outlet vent; said valve devices being removed prior to launch of said aircraft which allows circulation of air through a portion of said air intake means and said circulating passage during transportation of said munition on said aircraft,'said circulation preventing collection and freezing of water in said air intake means, and a spring loaded plug blocking access to said air conduit system.
3. A combination as set forth in claim 2 wherein said control system further comprises a shaft which precludes the removal of said spring loaded plug; and a lanyard fastened to said shaft and the structure of said aircraft; whereby said shaft is removed from said spring spring, thereby permitting said ram air to enter said fluid conduit system.
4. A combination as set forth in claim 1 wherein said control system further comprises an air filter in said air conduit system upstream of said pressure regulator and an electrical switch supported in close proximity to said actuator, said switch being-energized by said actuator to energize an electrical circuit which arms said munition.
5. A combination as set forth in claim 1 in which said apparatus of said control system comprises a support structure having a central axis which is supported on said munition so that it coincides with said reference axis, and a plurality of linear fluidic zero G sensors carried by said structure in a symmetrical manner about said axes, said devices being in flow communication with said inlet means and operating to assure provision of said usable output only when said apparatus is subjected to said sustained zero G environment resulting from free movement through said ambient air as evidenced by a zero G indication.
6. A combination as set forth in claim 5 in which in said apparatus of said control system said plurality of member operating to block flow of air into its associated second outlet conduit means while simultaneously allowing the flow of air into its first outlet conduit means under said conditions of sustained free movement to provide said useable output.
7. A combination as set forth in claim 6 in which said apparatus of said control system further comprises a hysteresis-inhibiting circuit operatively associating with the spherical member of each device to assure the spherical member has substantially the same force acting thereon under all conditions of said sustained free movement to thereby provide more reliable operation of said apparatus and control system.
8. A combination as set forth in claim 6 in which said apparatus of said control system further comprises a NOR fluidic logic device in flow communication with said inlet and outlet means, and wherein said plurality of devices is defined by a plurality of three devices spaced apart about said reference axis with each of said devices comprising, an enclosing wall defining a chamber, a spherical member carried within said chamber, inlet conduit means placing said chamber in flow communication with saidinlet means, first outlet conduit means serving as a vent for its associated device, and second outlet conduit means in flow communication with said NOR device, each spherical member operating'to prevent flow of air into its associated second outlet conduit means while allowing flow into its first outlet conduit means under said conditions of sustained free movement enabling flow of air from said inlet through said NOR device in an undiverted manner to said outlet to provide said useable output.